The invention relates to an apparatus for the wetting of seeds with active ingredients dissolved in a liquid. Such an apparatus includes a feeder and metering device with an opening directed from above into a spray chamber that is open at the bottom, in which an atomizer for the liquid active ingredient is located, and includes a mixing and discharge means under the spray chamber. In particular, the invention relates to an apparatus for the wetting of unginned cottonseeds which include lint, using active ingredients, such as, for example, insecticides or fungicides.
In agriculture, seeds are treated to protect them against fungi, insects, rotting and the like, by chemical means. For this purpose, the seeds are wetted in appropriate apparatuses uniformly with a liquid containing the necessary active ingredient. The uniform distribution of the active ingredient is important, as both an excessively high or low concentration can endanger the seed, in the first case by the active ingredient itself and in the second, by the lack of any effect. For this reason, a uniform flow of the seed is initially provided, for example by vibrating screening on a conveyor belt. Subsequently, the uniformly distributed material is wetted by the active ingredient on the conveyor belt. It is also possible to wet the seeds while they drop in a shaft.
Not all seeds can be separated by such simple means to obtain a uniform material flow. Cottonseeds, for example, have tiny hairs on their outer skin and therefore tend to form clusters which can no longer be treated by the conventional processes. For this reason, the seeds are delinted in a first working step in order to obtain the necessary material flow properties. Sulfuric acid or hydrochloric acid are customarily used in the process; flame scarfing is another process. After delinting, cottonseeds may be processed as described above.
In DE-A-3 239 867 for example an apparatus for the pickling of delinted seeds is described, in which the seed is divided by the centrifugal action of a rotating grain centrifuging disk, which is part of a metering device, in a treating chamber into a uniform cloud. A spray disk is located immediately following the grain centrifuging disk, which finely divides the liquid pickling agents in said cloud. By the inherent motion of the delinted seeds in this spray mist, the surface of each seed is wetted in a relatively uniform manner.
U.S. Pat. No. 3,155,542 describes a pickling apparatus for cottonseeds. In this apparatus the cottonseeds are brought into a treating chamber by means of a vertical auger type conveyor. In the chamber, they drop onto a rotating cone, which distributes the seed outwardly against the inner wall of the chamber. A rotating spray disk is located under the centrifugal cone, which produces a fine mist of the pickling agent. While dropping, the cottonseeds pass through the mist, whereby their surface is wetted. To prevent the cottonseeds, which are not entirely delinted, from balling up, spatula-like arms are provided to the right and the left of the screw conveyor as baffles, which project into the conveyor and are intended to separate the clusters of cottonseed formed. Although larger clusters are comminuted in this manner, cottonseeds, which are not completely delinted, cannot be scattered individually.
In the case of wet soil, delinting has a detrimental effect on the planting, as the hairs protect the seed against excessive wetness. For this reason delinting is often entirely eliminated.
Special machines are used for the wetting and pickling of cottonseeds that have not been delinted. For example, to separate clustered cottonseed, a vertical filler tube in such an apparatus leads into a truncated cone, the lower end of which opens into a wider tube forming the spray chamber. A rapidly rotating disk is located inside the truncated cone, directly under the end of the tube, which throws the seeds introduced against the walls of the truncated cone, from which they bounce back and drop in the more or less uniform distribution into the spray chamber. The metering of the material flow is controlled by varying the distance of the disk from the end piece of the filler tube, i.e., by the adjustment in height of the disk. For wetting, two other disks are rotating in the axis of the first disk, into the center whereof the liquid active ingredient is introduced. The rotation of the disk is intended to provide a fine, droplet shaped distribution of the liquid in the spray chamber. From below the spray chamber the seeds are transported by means of an auger conveyor into a chamber, wherein they are further mixed mechanically in order to distribute the wetting agent more uniformly over the surface of all of the seed grains.
An essential problem in the aforedescribed layout is posed by the material flow, which is difficult to control. A slight lowering of the rotating disks already leads to the separation of remaining clusters of cottonseeds. The spraying process is again not satisfactory, as the cottonseed in their free fall are not sprayed uniformly from all sides. Furthermore, too much wetting liquid is applied to the walls of the spray tube and is thus lost.